In a 360-acre field in the county of Northumberland, there are large beasts ten times rarer than the mountain gorilla and the Siberian tiger and three times rarer than the right whale. Humans haven't even touched them in centuries.

These are the Chillingham cattle, a wild subspecies that has lived in the same field for nearly a millennium. Unlike almost all other cattle in the United Kingdom — and indeed, the world at large — these cattle aren't domesticated, and it's possible but unproven that they might be direct descendants of the wild aurochs that roamed Europe before domestication. The Chillingham cattle are smaller than their domestic counterparts, weighing in at around 650 pounds, and they are so wild that they can't tolerate any direct human contact, as game warden Richard Marsh explains in a recent BBC article:

"No human hand touches them and they receive no veterinary care either... If humans were to handle them, they would change the way in which they smell. This would lead to any such beast being rejected by the herd and they'd kill them... By this time of year they've flattened the grass to the ground and any grass there is still growing will have no goodness - it'll all have gone into the root for next year. Surrounded with a fence means they cannot wander off and find food, so we have to keep them going, probably through to about March, with a couple of round bales of hay a day."

Outside of that indirect feeding, humans have to stay well away from the Chillingham cattle, and it's an arrangement that's worked just fine since around 1240, when it's believed that the field was first enclosed. The Chillingham cattle likely weren't the beneficiaries of 13th century conservation, but rather were protected as part of an effort to keep Scottish marauders out of royal lands. Despite centuries of inbreeding, these 90 cattle — and another 20 kept at a reserve location in Scotland — are still going strong, a sort of biological oasis from the modern ecological world.